Air-brake



(No Moden) R. E. MARSHALL. AIR BRAKE.

Pailsent'ed July 21', 1891.

UNITED STATES PATENT A OFFICE.-

'ROBERT E. MARSHALL, OF'VILMINGTON, DELA-TARE A'IR-BRAK E.

SPECIFICATION forming part of Letters Patent No. 456,199, dated July 21,1891.

Application filed May l, 1890- Serial No. 350,133. (No model.)

To all whom t may concern:

Be it known that I, ROBERT E. MARSHALL, of Vilmington, county of New Castle, State of Delaware, have invented a certain new and useful Improvement in Air-Brake Apparatus, of which the following is a true and accurate description, reference being had to the drawings which form a part of -this specification.4

My invention relates to the automatic pressure air-brake system orapparatus of railway-trains, and has for its object to so construct the said apparatus that the supply of air from the main reservoir to the trainpipe will be automatically cut off when the pressure in the train-pipe has reached a determined height without interfering with the air-puinp or with the accumulation of a. higher pressure in the main reservoir. This l accoinplish by placing an automatically-acting pressure-regulator in some part of the conduit or pipe system leading' from the main reservoir to the auxiliary cylinder or cylinders of the train.

Reference is now had to the drawings, which illustrate my invention, and in which- Figiire l is a side elevation of part of a railway-train equipped with my improved device; Fig. 2, a central sectional elevation of a pressure-regulator well adapted for use in my improved apparatus, and Fig. 3 a crosssection through the regulator on the line X X of Fig. 2.

A is the locomotive; B, the tender; C, a railway-car. D is the steam-pump; E, the air-pump; F, a conduit leading from the airpiiinp to the main reservoir G; Il, a pipe leading from the main reservoir to tue engineers brake-valve I; J, a pipe leading from theA brakevalve and constituting part of the train-pipe. A

J J are sections of the train-pipe attached, respectively, to the tender and the car.

K K are thecouplings of the train-pipe.

jj are branches leading from the train-pipe J to the auxiliary reservoir L L.

In all of the above-noted features i my apparatus is of the usual kind and is used with the well-known supplementary devices, brakecylinders, &c., which, as they may be o f any usual construction, I have not thought it necessary to show in the drawings. n

M is an automatic pressureregulator,which I place in some part of the conduit leading from the main reservoir to the auxiliary reservoir, preferably, as shown, in the pipe connecting the. engineer-s brake-valve with the main reservoir.

N is a pipe connecting the pressure-regulator with some part of the pipe on the delivery side of the pressure-regulator.

Referring now to the construction of the pressure-regulator shown in Fig. 2, it consists of a casing 1W having formed in it the chambers m and m', connected by a passage in which is formed a valve-seat m2. A port oi' passage ym3 connects the chamber m with the pipe leading fiom the main reservoir, and a port or passage m4 connects the chamber m' with the pipe leading to the train-pipe, or, preferably, to the engineers brake valve. m5 is a valve arranged to close the passage m2. This valve, as shown, is a balanced valve, its upper part moving in a bearing m, formed above the chamber m. `A small port m7 should be left to permit air to escape from lthe chamber m to the top of the balanced valve.v m8 is a spring situated between the top of the balanced valve and a valve mi, which is arranged to close a passage m17, which leads to an escape-pipe m10, and also, as shown, to the lower part of a chamber in, formed above it. In this chamber is a diaphragm m12, and secured to this diaphragm is a rod m13, which moves in a chamber ml and upon which is an adjusting-nut m14. A spring mlis arranged, as shown, to press the rod m13 up and normally keep the diaphragm in its uppermost position. The lower part of the spring rests on a shoulder m1, formed at the bottom of the chamber m1. m" is a screwrod, by which the valve m5 can be held to its seat or allowed a certain amount of movement from its seat.

The operation of the device is as follows: The rod m9 is screwed down, so as to permit the valve m5 to leave its seat and open the passage between the chambers m and m. The spring m8 pressing it down as fai' as it can go, the air from the main reservoir then passes through the regulator unchecked until the air in the auxiliary reservoir and trainpipe has reached the determined pressure, at

which, passing through the pipe N into the chamber mi and thence to the top of the dia- ICO phragm m12, it will overcome the power of the spring m15 and press the diaphragm down. The downward movement of the diaphragm, which rests upon a plate connected with the valve m16, presses this valve also down, open ing the connection between the upper side of the balanced valve m5 and the escape'pipe m10. The pressure on the upper side of the balanced valve is thus removed, and it of course immediately rises, closing the passage m2 and cutting off any further supply of air from the main reservoir to the train-pipe. The steam-pump, however, continues to operate and pump additional air into the main reservoir, in which, ot course, the pressure soon greatly exceeds that in the train-pipe. As soon as the pressure in the train-pipe is released by the act ot setting the brake the pressure on the upper side of the diaphragm m12 will fall below that necessary to compress the spring m15, which spring will therefore draw up the diaphragm. The spring m3 then moves the valve m16 up, closing the passage m17 and permitting the air passing around through the small port m7 to accumulate above the top of the balanced valve, which will of course move downward and open the passage m2. This passage being opened, the high-pressure air accumulated in the main reservoir will rush with great quickness to reill the train-pipe and the auxiliary reservoir.

Any of the many well-known forms of pressure-regulators can be used in connection with myimproved apparatus. The one illustrated in the drawings is well adapted for the purpose, and is now in quite general use to regulate the operation of the steampump used in connection with the air-pump of airbrake apparatus. The said pressure-regula tor in itself forms 11o part of my invention.

It must be understood that by the automatic pressure air-brake system I referto the system of which the NVestinghouse automatie pressure air-brake is the best-known example, and my invention has no relation to the systems known as the vacuum system and the direct-pressure system.

Having now described myinvention, what I claim as new, and desire to protect by Letters Patent, is-

l. In a railway automatic pressure airbrake system having main and auxiliary reservoirs, as described,the combination ,with the pipe or conduit leading from the main reservoir on The engine to the auxiliary reservoir or reservoirs, of a p1essureregulator arranged to automatically cut oit the supply of air to the train-pipe when it has reached a certain pressure therein, substantially as and for the purpose specified.

2. In a railway automatic pressure airbralie system having main and auxiliary reservoirs, as described, the combination,\vith the pipe leading from the main reservoir to the engineers brake-valve, ot a pressure-regula tor arranged to automatically out off the supply of air to the train-pipe when it has reached a certain pressure therein, substantially as and for the purpose specified.

R. E. MARSHALL. ifitnesses` Lriwis R. DICK, FRANCIS T. CHAMBERS. 

